1. Field of the Invention
Corneal topography is a diagnostic technique to measure, generally, the shape of the anterior surface of the cornea. Such measurements are important for determining the refractive optical characteristics of the human eye in refractive surgery and for the design of intraocular lenses (IOLs). A corneal topogram, providing the corneal shape, is required also for fitting of contact lenses. A concept for a novel corneal topographer is described in the present document.
2. Description of the Related Art
Current cornea topographers generally project a set of concentric rings on the anterior cornea and analyze the reflections, i.e. the Placido disc, for changes in shape versus a reference image. The irregularities of the corneal shape can be recalculated from the geometrical distortions of the reflected image. Other corneal topographers use wave-front sensing (e.g., the Shack-Hartmann method) for corneal surface characterization. The present invention is based on measuring absolute distances to the sub-regions of the cornea by analyzing the spatial spectrum of the reflected light.